Re: [PATCH 1/4] Revert "migration: modify test_multifd_tcp_none() to use new QAPI syntax"

[Peter Xu]

On Thu, Apr 11, 2024 at 07:45:21PM +0530, Het Gala wrote:
> 
> On 10/04/24 8:23 pm, Peter Xu wrote:
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> > 
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> > 
> > On Wed, Apr 10, 2024 at 10:04:33AM -0300, Fabiano Rosas wrote:
> > > Het Gala <het.gala@nutanix.com> writes:
> > > 
> > > > This reverts commit 8e3766eefbb4036cbc280c1f1a0d28537929f7fb
> > > > 
> > > > After addition of 'channels' as the starting argument of new QAPI
> > > > syntax inside postcopy test, even if the user entered the old QAPI
> > > > syntax, test used the new syntax.
> > > > It was a temporary patch added to have some presence of the new syntax
> > > > since the migration qtest framework lacked any logic for introducing
> > > > 'channels' argument.
> > > That wasn't clear to me when we merged that. Was that really the case?
> > Yeah these look all a bit confusing..
> > 
> > I'm wondering whether do we need the new interface to cover both precopy
> > and postcopy, or one would suffice?
> > 
> > Both should share the same interface.  I think it means if we covered the
> > channels interface in precopy, then perhaps we don't need to test anywhere
> > else, as we got the code paths all covered.
> > 
> > We actually do the same already for all kinds of channels for postcopy,
> > where we stick with either tcp/unix but don't cover the rest.
> Do we want to add other transports too (vsock, exec, rdma) with the new
> interface ?
> I believe we have tests for fd based migration

Het,

What I meant is we used to do white box testing for migration, trying to
cover all the code paths would suffice for us in that case.

It means maybe we don't need the postcopy test to cover the channels
interface as long as precopy has covered that and also if that covered all
the "channels" abi then we should be safe.

What I worry is we keep extending the test matrix but we're actually
testing the same code paths.  Then the test runs slower each time, we burn
more cpus for each CI kick, but without a real beneift.

Thanks,

-- 
Peter Xu